Charges can be generated and can accumulate on a component, or a device under test (DUT), from sources such as the nozzles, suction cups, or pick-up mechanisms, on automatic handling equipment used to move the DUTs. Abrupt or rapid electrical discharge may be referred to as an electrostatic discharge (ESD) event, and may occur when the charged DUT contacts the test pins in the test interface unit (TIU). Persistent, or singular, ESD events can cause catastrophic and/or latent failures of the DUT. ESD events can also negatively impact the quality and reliability of the device.
As the number of terminals on electrical components increases, the number of, and the severity of, ESD events typically increases. As components get more complex the number of terminals typically increases.
Proposed solutions to this problem include installing air ionizers in the testing environment, or using test pins with retractable static dissipative caps. However, each of these proposed solutions have problems. ESD events may happen so quickly that it is typically not possible for ionizers to completely neutralize a charge that may have accumulated on the device to be tested. Static dissipative test pins are expensive.